Not much has changed since October of 2025.

That, as of July 2026, is the story of the starry stonewort infestation in Middle Cullen.

Last October, when scuba divers conducted a perimeter survey, the infestation was about 6.4 acres. This summer, based on a perimeter survey conducted on June 26, the infestation has grown to about 6.9 acres. The small increase is due largely to some expansion along the northeast shoreline, where a narrow line of growth has become a bit wider.

The CLA used the June 26 survey by Blue Water Science of St. Paull as the basis for contracting with Lake Restoration, Inc. of Rogers, Minn., which applied a federally approved and state regulated copper algaecide/herbicide to algae shortly after the Fourth of July. A follow-up scuba survey will be conducted in a few weeks to assess the results of this treatment. A second treatment is planned for later this summer, and a third treatment will likely be conducted in September or October.

The CLA is largely following the starry stonewort treatment strategy it adopted last year, which is to hit it hard, hit it often and do what we can to keep it where it is. Unlike last year, we did forego a June treatment based on findings from last year that our June treatment wasn’t particularly effective. It wasn’t effective because the algae had not yet grown to a length where an algaecide could do a good job of knocking it back. So, this year, in a move to make member donations stretch further, we passed on the June treatment. This decision was supported by the DNR and several other starry stonewort experts.